Grinding machine



July 6, 1965 E. J. G. scHAAR 3,

GRINDING MACHINE Filed Oct. 2, 1962 8 Sheets-Sheet l IN VEN TOE. ETIENNE LJ 6.

y 1965 E. J. G. SCHAAR 3,193,114

GRINDING MACHINE Filed Oct. 2, 1962 8 Sheets-Sheet 2 INVENTOE. ETIENNE LJG. SCHAAR July 6, 1965 E. L. J. G. SCHAAR GRINDING MACHINE 8 Sheets-Sheet 3 Filed 001,. 2 1962 I I I I II N \RN a N k. m Tl V July 6, 1965 E. L. J. G. SCHAAR 3,

GRINDING MACHINE Filed Oct. 2, 1962 a Sheets-Sheet 4 IN VENTOE ETIEN E. .JG CA7"? -rfl July 6, 1965 E. J. G. SCHAAR 3,

GRINDING MACHINE Filed Oct. 2, 1962 s Sheets-Sheet 5 INVEN TQE. ETIENNE LJ CHAAR July 6, 1965 E. L. J. G. SCHAAR 3,

GRINDING MACHINE Filed Oct. 2, 1962 8 Sheets-Sheet 6 1965 E. L. J. G. SCHAAR 3,193,114

GRINDING MACHINE Filed Oct. 2, 1962 8 sh t s 7 [N vE/vroe. ETIENNE L416 5CHAA/Z July 6, 1965 E. J. G. SCHAAR 3,193,114

GRINDING MACHINE Filed Oct. 2', 1962 8 Sheets-Sheet 8 United States Patent 3,193,114 GRENDKNG MAtJl-HNE Etienne L. J. G. Schaar, Marly-le-Roi, France, assignor to Norton Company, Worcester, Mass, a corporation of Massachusetts Filed Get. 2, 1%2, Ser. No. 227,393 14 Claims. (Cl. 214-31) The present invention relates in general to the grinding of billets, flat bars, slabs, blooms and similar metallurgical products, particularly to supporting means therefor with means for positioning various sides of a workpiece to be ground.

The effecting of such grinding on machines provided with a movable grinding wheel carrier is known, whereby, for purposes of the operation the carrier is brought into a position where the workpiece can be worked on by the grinding wheel. Means have already been sought to make these machines semi-automatic, and one of the problems that present itself is that of positioning the billets, flat bars and other products on a work support so that the various surfaces may be conveniently exposed to be worked upon. Several solutions have previously been proposed, but existing machines offer a number of disadvantages which the instant invention is intended to remedy.

In a certain class of steel plants grinding of the several pieces is generally done in a non-uniform series, that is, often the grinding of a few square-section billets may be followed by the grinding of flat bars, or the grinding of workpieces having one given cross-sectional shape is followed by other workpieces having diiferent cross-sectional shapes. It is therefore necessary that means be provided whereby the various workpieces may be caused to be turned by the device itself to expose the various sides to be ground while the machine mus-t be considered from the viewpoint of providing for easy and rapid regulation so as to be adaptable to the various cross-sections of the various workpieces to be ground.

The main object of the invention is to provide apparatus that is capable of being operated to semi-automatically index workpiece-s of various cross-sectional shapes no matter in whatever order they are presented to expose all sides of all the pieces for grinding.

The invention is shown embodied in a grinder consisting of a column in association with a grind-stone holder or carrier, and a frame and carriage which receives and supports the workpiece to be treated, worked upon and by reference to which the grindstone carrier is movable. The frame takes the form of a plane of reference associated with a stop-piece on a work supporting surface, a movable table, the motion of which takes place with a vertical component and forms a resting plane for the workpiece to be worked on. The machine has devices that hold the workpiece during the operation and then eject it after the operation and includes a system that controls the movement of the table between an upper plane with a position determined in respect of the plane reference and a lower position which can preferably be regulated.

According to one possible arrangement, the stop-piece is set back from the edge of its supports which lie in the plane of reference on the frame so as to provide a supporting ledge for a portion of the workpiece. The change in position of the table when it is lowered with respect to the plane of reference on the frame, is used in conjunction with the support provided by the supporting ledge and the stop device which permits only an edge of the workpiece to be disposed on the ledge, to effect a turning of the piece or the semi-automatic rotation or indexing of the workpiece.

According to the preferred form of the invention, the table is mounted on at least one articulated parallelogram system, one of the pivoting shafts of which is rotated by a lover or some other device that is actuated in a positive manner, as for example by a jack or the like. The control mechanism of the latter device causes movement of the table with a vertical component, either raising or lowering it. Such movement is advantageously effected on the line of the arc of a circle, and to reach its predetermined or fixed upper position, the table will preferably move through the summit of its movement and then move a little beyond the summit of its course, so that when the motion is reversed to effect its descent at the start of such movement, a slight upward shift of the work initiates the rocking motion thereof and continued movement of the table completes the rotation of the workpiece being worked on. This articulated paralleogram system, simple or multiple, is advantageously so mounted that the movement downward of the table is effected with a component that is oriented longitudinally to the workpiece, which further facilitates rotation. The extent of the table movement downward can be limited by any well known means such as a mechanical stop-piece, suitably adjustable according to the size of the piece to be worked upon.

The mechanism controlling the table may, according to another feature of the inveniton, be kept in place by a pneumatic lifting jack, advantageously in conjunction with a hydraulic damper.

The holding and ejection attachments in the simplest form .include at least a crank lever, mounted pivotally upon the frame and constructed to hold the workpiece with one arm and with the other to eject it. This lever is preferably so mounted that its arms will move on a plane that is perpendicular to the axis of the materials to be ground, and its motion can be controlled, for example, by a pneumatic jack.

Since the workpiece to be treated is generally quite long, provision should be made for several of the above described hold-and-ejection levers as well as several pneumatic jacks placed at intervals along the length of the machine. In order to assure a uniform grip, even in the case of a warped or twisted workpiece, the levers could be mounted on a shaft the characteristics of which are so worked out that it will act as a torsion bar between the various levers.

As the machine has to be able to work with workpieces of varying lengths, it should advantageously consist of several tables each of which is associated with at least one system of articulated parallelogram support means. In order to achieve the desired synchronization in the control of the various tables, there should preferably be provided a single controlling mechanism, and the articulated pa-rallelograms of the tables should, for example, be connected by means of one or more connecting rods.

It will be observed that the machine according to the invention, permits rotation of the workpieces because of the relative movement between two planes, namely, a plane of reference in which the work is held to be ground, the plane being formed in part by the table when it is in its upper position on the support ledge that is even therewith for supporting a workpiece on the frame. The relative movement between the parts is here achieved thanks to the motions of a pivotal character, without any sliding or shifting of the contacting parts, which is a very important factor in a machine of this kind, as research has shown that sliding or rubbing motions are incompatible with the work to be done, that is, with the conditions created in a dusty environment of an abrasive grinding operation. It will also be observed that the mechanisms are advantageously operated by means of pneumatic systems, which in particular eliminate the possibility of leaking oil such as could very well accompany the use of hydraulic apparatus.

or carriage, on an enlarged scale taken approximately the manner in which a flat bar is loaded onto, rotated and ejected by the mechanism, and

FIG. 15 is a schematic view showing the ejection of a flat bar from the machine.

The grinder as shown in FIG. 1 comprises a main frame 1, whereon is mounted a movable grindstone carrier 2, which holds a rotatably driven grindstone 3 that is. to do the grinding. Theapparatus for rotating 'the grindstone 3 has in general been designed in a well known manner indicated byreference 4. The machine consists in addition, of a movable frame or carriage 5, which receives and supports the workpiece 6 to be ground and which by means of the rollers 7 and rotatably fixed to the carriage 5 and a member 8 respectively, said the member 8 being fixed relative to carriage 5, is movable n upon a flat rail 9 and a V-rail 9a, which rails are fixed to the bed 11 (FIG. 2)' of the machine proper. Movement of the carriage is effected by a toothed rack 12 carried by and fixed to the frame of the carriage, with which meshes a toothed wheel"13 rotatably journaled in the bed. At 14 there is shown in a. general way the control station and the machine operator.

The apparatus for grinding the workpiece has not been described in detail since it forms no part of the invention, which concerns itself more especially with the apparatus and the manner by which the various workpieces such as billets, flat bars, slabs, blooms, and the like, are rotated for purposes of grinding their various surfaces. v 7

The carriage or frame 5 has a plurality of spaced elements forming a working table which are best seen in FIGS. 2 and 4. One portion is formed of the top surface 15 of the carriage 5 which has a stop means '16 fixedly positioned in any desired place on the upperv face 15 of-the carriage 5 as shown in FIG. 3, and are positioned adjacent the edge of ledge 1611 as shown in FIG. 7, so' that the center of gravity of the piece'being ground overhangs, the'ledge for a, purpose that will appear more fully below The spacingof stop pieces 16 near the edge fofthe top surface 15 of the. carriage 5 pro.- vides a ledge'for a purpose that will appear'below, and the ledge'is adapted to cooperate with and support a portionof the workpiece being ground, the remainder of the workpiece being supported on one or more movable tables 18; which are adapted to move between the full line and dotted line positions shown in FIG. 4.

I The machine may be provided with an inclined feed chute17 for delivering a workpiece onto the table into 4. and table tops'18 to be carried under the grinding wheel as the carriage is driven back and forth by the rack and pinion 12 and 13., It is obvious that other means than chute 17 could be provided'for feeding a workpiece into position on the table top. I 7

As is best shown in FIGS. 2 and 3, frame or carriage V 5 has a number of separate table elements 18 which serve as supporting surfaces for the workpiece in the course of the work, as explained hereinbelow. The machine shown has two tables 18 of different sizes, so that the shorter workpiece may rest upon the shorter table and the medium-size workpieces upon the longer table, while long workpieces may be supported simultaneously upon both of the tables. Each table 18 is supported by sets of rods or levers 19, each of which is pivotally connected, at one end, to the underside of the, table, and on the other end fixed to a shaft 22. journaled in bearings 20 on the frame 5 of the machine. These sets of rods or levers disposed at the. opposite ends of the tables and on each side forman articulatedparallelogram, as is clearly evident for the shortest table 18 in FIG. 3. In this figure every table 18 has been rep resented by solid lines in its predetermined upper position, and by phantom lines as 18a in the lower position, which positions can be regulated as desired by any well known means, such as a mechanical stop-piece or lug (not shown), or by controlling the stroke of the actuating means. The tables move to their lower positions by traveling through an arc of a circle, as shown by the arrow 21 in FIG. 3; the rods or levers 19 of the sets, of articulated parallelograms then pivoting about the axes of shafts 22 supported in the bearings 20.

The two coupled rods or levers 19 disposed on either side of the table'associated with a set 'of articulated parallelograms are keyed to a shaft 22, which is carried in the bearings 20. One of the shafts 22,has fixed to it, as shown in FIGS. 2 and 3,21 control lever 23. and a damper lever 24 connected with the shaft at one end while the other end serves to control the movement of the tables. As shown in FIG. 3, the free end of one of the levers 23 is pivotally connected to and actuated by the piston rod 25 of a double action pneumatic jack or cylinder 26, while the free end .of lever24 associated therewithis pivotally connected to and its motion is controlled by piston rod 27 of a hydraulic damper 28. As shown in FIG. 2,'the jack 26 and the damper 28 are mounted so as to pivot upon frame 5 in journals and 30, in order that they may pivot 'or move in the degree required upon actuation of the table.

Further, and as shown in FIG. 2, one of the lever rods 19 on each table has integral therewith an arm 31', and the arms 31 on each table are connected together by means of a tie-rod 32, so that only a single control jack or cylinder 26 is needed in order to ensureasynchronous up and down movement of the tables. I

As shown in the drawings, FIG. 3 the system as a whole, formed by the tables and their control elements, is disare driven slightly over their centers when the tables occupy their upper position, in which position the upper surfaces of the tables serve as planeor support surfaces 1 for'the workpieces which are on a levelgwith'the plane of top surface 15 of carriage 5. After a grinding operation has been completed on one side of a workpiece,ithe tables 18 are lowered but first there is a sligh-tmovernent upward beyond the surface or plane of reference 15, as the tables move up to the top of the arc and start their descent to the position before the stop16. The chute 17 is placed to lower position represented by phantom lines in FIG. 3. This shifting of the tables downward is obtained by reason of the link system having the arc movement which moves the tables in a longitudinal or translational movement, and the character of the shift in table position so obtained is such as to facilitate the rotation of the work-.

pieces by inducing a rocking action therein as described hereinbelow.

The machine also comprises hold down and ejecting levers, consisting of a holding arm 34 and an ejecting and indexing arm 35. These levers are fixed to a longitudinal shaft 36 which is journaled to pivot on the frame 5 and, as shown in FIG. 4, has the arms 37 keyed thereto which are actuated by the piston rods 33 of the pneumatic jacks on cylinders 39, a plurality of which may be supported at spaced points on the frame 5 to pivot in the journals 40 on the bearing supports 41 which are fixed to the frame 5. Such a mounting permits the cylinders 39 to have the required rocking motion to follow their piston rods 38 upon actuation of the hold-and-eject levers 34, 35. As shown in FIG. 3, levers 34, 35 and the pneumatic cylinders 39 are distributed along the length of the machine, and the shaft 36 together with the plurality of cylinders 39 possesses such characteristics that the drive shaft 36 operates in the manner of a torsion bar and effects a uniform holding action regardless of the shape of the warped or twisted workpieces.

In the drawings the control system including valves and distribution pipes terminating in the various jacks or cylinders are not shown, since they can be any of the well known commercially available type. It is understood that the pneumatic control avoids all manner of pollution, such as that which in the case of hydraulic circuits could be caused by possible leakages, and that the absence of a sliding movement in the linkwork control of the tables and holding levers eliminates the possibility of there being any binding which might otherwise occur under the conditions associated with the use of a grinding machine.

Let us now describe the feature of automated rotation of the workpiece in the process of its being ground. We shall first refer to FIGS. 5 through 9, to best show the rotation of a square-section billet after each side is ground in order that its four surfaces may be worked upon.

At the start of the operation a billet 43 is fed to the table by sliding down the inclined chute 17 onto the tables 18 into the position represented at 43a in FIG. 5. At this stage, table 18 is in its upper position on a level with the ledge 16a forming a plane of reference 15, while levers 34 and 35 occupy an inactive position.

Shaft 36 is then operated to drive lever arm 34 to slide the workpiece 43 on the tables 18 onto the projecting ledge 15a of the plane of reference 15 and toward stop 16, for thereafter pressing and holding the workpiece or billet 43a against the stops 16 as in FIG. 6. The billet so held, can then be ground on its upper surface.

When the grinding of this surface is completed, the operator causes table 18 to descend as shown by the arrow 44 in FIG. 7, this movement being accomplished by actuation of jack or cylinder 26 driving links 23, 24 and 19; arm 34 drops into the position shown in FIG. 7 by feeding air to cylinder 39 which rot-ates shaft 36. The billet is firs-t lifted and then tends to descend with the table but, as shown in the drawing at 4312, it is held back by the projecting ledge 16a of the plane of reference 15 extending beyond the stop piece 16 and so it tends to turn due to the fact that the center of gravity of the workpiece overhangs the ledge 16a of the plane of reference 15. This rocking movement is assisted, as we have pointed out above, by the fact that table 18 first moves slightly upwards before starting to move down, which transmits motion to the billet to produce a rocking action over the ledge.

Following this rocking movement, the billet takes the position shown at 43c in FIG. 8. At this juncture, the operator causes the table to rise again as indicated by arrow 45, and the links 13 raise the tables 18 .to the level of the plane of reference 15. The shaft 35 is then rotated as shown in FIG. 6 to drive arms 34 into position to hold the workpiece 43 against stops 16 with the second side of billet 43 exposed in position to be ground.

The rocking or turning operation is carried out three times after the initial grinding step in order to bring the three other surfaces of the square section billet 43 each in its turn into the grinding position. Then, as shown in FIG. 9, shaft 36 is rotated so that lever arm 35 is moved clockwise as shown in FIGS. 8 and 9 in order to ensure ejection of the billet 43 from position 43d as indicated by arrow 46. The billet pushed by arm 35, drops into chute 47 which is positioned on one side of the operators station so that carriage 5 may be moved into position in front of the chute.

schematically in FIGS. 10 through 15 the manner of feeding, rotating and ejecting flat bars after grinding has been shown. At the start of the operation, flat bar 48 slides down the chute 17 onto the table .18 and occupies the position shown at 48a. The operator then sees to the movement of lever arm 34 in order to press the fiat bar 48a against the stops 16, as shown in FIG. 11. In this position, one of the large surfaces of the flat bar which faces upwardly can now be ground.

When this grinding operation has been completed, the operator causes table 18 to descend as shown at 49 in -FIG. 12, after lever arm 34 has been moved to the position shown and the flat bar tends to move down with table 18 except that one edge thereof 'is retained by the ledge 16a of the plane of reference 15 which extends beyond the stops 16, and the fiat bar is caused to rock to the position 4815 shown in FIG. 12. The arm 34 is now actuated to clamp the bar and as shown in FIG. 13 the flat piece may be held against the front of ledge 16a with the nose of lever 34.

The flat bar is now held on the table 18 in an edgewise position as shown at 48c in FIG. 13, and it is pressed by the lever arm 34 against the vertical edge surface 50 of frame 5 adjacent the plane of reference 15. Table 18 can be retained in this predetermined lower position by engagement with suitable stops 50a and 5017 which may be fixedly supported from frame -5 of the carriage. It can be seen that in this manner the flat bar is held quite stable and its narrower surface now facing up- Wards can thus be ground without danger of its shifting, as would be the case for a flat bar that is fairly thin but relatively wide.

In FIG. 14-, the position 480 occupied by the flat bar at the time of the last described operation is indicated by dotted lines. The operator then proceeds to effect the movement clockwise of the lever arm 35 in a rather sudden manner, in such a way that the end of arm 35, by striking the upper part of the flat bar held edgewise, causes it to fall as indicated by arrow 51. Now the flat bar takes the position shown at 48d in FIG. 14. The operator then proceeds to raise the table 18, as shown by arrow 52, to position the fiat bar in the position 48a shown in FIG. 10, so that the flat bar can again be pressed against stops 16 and the third surface can be ground.

The motions shown in FIGS. 12 and 13 permit the grinding of the second narrow edge surface, and then the flat bar, the four surfaces of which have been ground, can be removed from the table 18, by means of arm 35, as shown at 48e in FIG. 15; the movement of the flat being represented by arrow 53 leading into chute 47.

It can be seen that the present invention provides a means to effect the step-wise rotary indexing of Workpieces having straight sections and varying dimensions for machining the sides thereof, regardless of the sequence in which they are presented.

It is apparent that various control means may be provided whereby the operator may shift the various elements of the machine as he desires. While the above covers a preferred form of the apparatus it is apparent that many modifications of the invention may occur to those skilled in the art, which will fall within the scope of the following claims.

I claim:

1. An indexing mechanism for turning workpieces having various cross section comprising a frame, a work supporting ledge on the frame formed of a fiat generally horizontal surface intersecting a vertical surface, a work stop on said horizontal surface set back from the vertical surface, a movable fiat work supporting table adjacent the ledge, said table having a work supporting surface disposed in a generally horizontal plane, means to produce vertical movement of said table along said vertical surface and being adapted to maintain the top surface of said table in any one of a number of positions including a position coincident with said horizontal surface of said ledge-and in positions generally in aplane parallel to and below said horizontal surface, means to move the workpiece across the table towardsfth'e work stop and to hold the workpiece during machining against said work stop and alternatively against the vertical surface 'of said ledge when the table is-below said horizontal tem of levers and shafts, a control lever to one of the shafts and actuated by at least one operable pneumatic cylinder.

3. A work indexing mechanism according to claim 1 in which the means to produce vertical movement of the table includes means to raise the top surface of said table above and substantially parallel to the plane of the horizontal surface of said ledge.

4. A work indexing mechanism according to claim 1 in which the plane of the horizontal surface of the work supporting ledge is located below the highest point attained by the top surface of the table during the movement of said table to and from its upper work supporting position.

5. A work indexing mechanism according to claim 1 in which the means to produce vertical movement of said table includes pivotally mounted hydraulic damper means in association with pivotally mounted pneumatic-actuating means. a j

6. A workindexing mechanism according to claim 1 in which the means to hold the workpiece during machining andv means for ejecting said workpiece from said table comprises pivotally mounted opposed .lever arms, said arms adapted to contact opposite sides of the workpiece, means to pivot said lever arms selectively clockwise and counter-clockwise. substantially perpendicular to the axis of the workpiece. V l

7. A work indexing mechanism comprising a. carriage, a work supporting ledgeon the carriage comprising atop surface intersecting an edge surface, a work'stop on said top surface set back from the edge of said ledge, a plurality of spaced pivotally mounted movable generally horizontally disposed work supporting tables adjacent the edge ofsaid ledge, meansto produce simultaneous synchronous translational movement of all of said tables in an arc path in substantially the same plane a fixeddistance from and parallel to said workstop to cause the workpiece to be moved from and lifted above the ledge and drop back onto said, ledge, said ledge countering the down ward movement of and indexingthe workpiece asthe tables move to a lower position, means to maintain the top surfaces of said tables on the horizontal plane of said top surface of said ledge and in selective positions .parallel to and below said horizontal plane, means to move the workpiece across the tables towards the work'stop and to hold the workpiece duringf machining against said work stop when said tables are maintained on the horizontal plane of said top surface of said ledge and against the edge surface of said ledge when the tables-ar'eLriiairitained below said horizontal plane, means for initiating a,1ss,11a

8 ingsaid workpiece from said chiming operation. i .8. A work indexing mechanism according to claim 7 in which the means to produce simultaneous synchronous translational movement ofall'of said tables on an arc includes an articulated parallelogram system of levers and shafts for each of said tables, a control lever fixed to one of the shafts of each system interconnected and actuated in unison by a single means.

9. A work indexing mechanism according to claim 7 in which the means to produce simultaneous synchronous translational movement of all of saidtables on an arc includes means to raise the top surface of each of the tables to the same plane above and parallel to the plane of the horizontal top surface of the ledge when said tables are traversed on said arc.

10. A work indexing mechanism according to claim 7 in which the means to produce simultaneous synchronous translational movement of all of said tables on an arc includes a single pivotally mounted damper means in association with a single pivotally mounted pneumatic actuating means. V v i 11. A work' indexing mechanism according to claim 7 in which the means to hold the workpiece during machining and the means for ejectingthe workpiece from the tables comprises a plurality 'of levers, fixed to a pivotally mounted torsion drive bar and placed at intervals-on the torsion drive bar along the length of the mechanism adjacent to and between said horizontal work-supporting tables, said levers havingopposed lever arms adapted to contact opposite sides 'of the workpiece, actuating means adjacent eachof said levers being pivotally connected to said torsion drive bar to oscillate said bar and said'levers together selectivelyclockwise and counter-clockwise substantially perpendicular to the axis of said workpiece, said actuating means being adapted to stress said torsion drive bar in one direction to assure a grip of the workpiece by the lever arms on the same side of the workpiece when the mechanism is handling warpedor twisted workpieces.

1 2. Apparatus for indexing workpieces of various cross section comprising a traversable carriage, a work supporting ledge on the carriage, a work stop on said ledge set back from the edge of said ledge a distance whereby at lease one-halfthe weight ofa workpiece overhangs said edge, a pair of pivotally mounted movable generally horizontally disposed Work supporting tables of different length adjacent the edge of said ledge, means to produce simultaneous synchronous translational movement of said tables in an arc in substantially thesame generally vertical plane a 'fixed distance from said ledge are causing the workpiece supported thereby to be moved from and lifted above the ledge and drop back onto said ledge, said ledge countermg'thedownward movement of and indexing the workpieceas the' tables move to a lower position, means to maintain the top surfaces of said tables on the hori zontal plane of said ledge and in selective positions parallel to and below said horizontal plane, means to move the workpiece across the tables toward the work 'stop and to hold the workpiece during machining against said work' stop when said tablesare maintained in a plane opposite said edge and against said edge surface when the tables are below said horizontal plane, means for initables after thefinal matia'ting an indexing movement of the workpiece situated on the tables when said tables are below said horizontal plane and for ejecting said workpiece from said tables after the final machining operation. A

13. Apparatus for indexing workpiecesof various cross section comprising a traversable carriage," a plurality of work supporting ledges all in the same plane, 'a work stop on said ledgesset'back from the edges of said ledges a distance whereby at, least one-half the weightof the workpiece overhangs said edges, a pluralityof pivotally mounted movable work supporting tablesadjacent the ledges, means including at least one articulated paralleloan indexing movement of a workpiece .situated on the tables when the tables are below said plane and for ejecta gram system of levers and shafts to produce translational movement of said tables on an are, causing said workpiece to be moved from and lifted above the ledge and back onto said ledge, said ledge countering the downward movement of and indexing the workpiece as the tables move to a lower position, means including a controlled fluid motor to maintain the top surfaces of said tables on the plane of said ledge and in any one of several selective positions parallel to and below said plane, means including a plurality of movable lever arms fixed to a torsion bar to hold the workpiece during machining against said work stop and alternatively against the edges of said ledges when said workpiece is supported below said plane, means for initiating an indexing movement of a workpiece situated on the tables when said workpiece is supported below said plane and for ejecting said workpiece from said tables after the final machining operation.

14. A work indexing mechanism for a billet grinder comprising a traversable carriage, work supporting ledges each comprising planar top surfaces intersecting with edge surfaces, a work stop on and extending across said top surfaces set back from the edges of said ledges a distance whereby more than one-half the weight of a workpiece overhangs said edges, pivotally supported movable work supporting tables adjacent the ledges, means to produce simultaneous synchronous translational movement of said tables on an arc, causing said tables to be moved from and lifted above and lowered below the planar top surfaces of said ledges, said ledges countering the downward movement of and indexing the workpiece as the tables move to a lower position, controlled actuating means to maintain the top surfaces of said tables on the plane of said top surfaces of said ledges and in selective positions parallel to and below said plane, pivotable mean at spaced intervals including a torsion bar to hold the workpiece during machining against said work stop and alternatively against the edge surfaces of said ledges, pivotable means for initiating an indexing movement of a workpiece of certain cross section supported on said tables in a position below said plane and for ejecting said workpiece from said tables after the final machining operation.

References (Iited by the Examiner UNITED STATES PATENTS 5/56 Evans. 7/63 Vekovious et al.

FOREIGN PATENTS 5/57 Germany.

25 HUGO O. SCHULZ, Primary Examiner. 

1. AN INDEXING MECHANISM FOR TURNING WORKPIECES HAVING VARIOUS CROSS SECTION COMPRISING A FRAME, A WORK SUPPORTING LEDGE ON THE FRAME FORMED OF A FLAT GENERALLY HORIZONTAL SURFACE INTERSECTING A VERTICAL SURFACE, A WORK STOP ON SAID HORIZONTAL SURFACE SET BACK FROM THE VERTICAL SURFACE, A MOVABLE FLAT WORK SUPPORTING TABLE ADJACENT THE LEDGE, SAID TABLE HAVING A WORK SUPPORTING SURFACE DISPOSED IN A GENERALLY HORIZONTAL PLANE, MEANS TO PRODUCE VERTICAL MOVEMENT OF SAID TABLE ALONG SAID VERTICAL SURFACE AND BEING ADAPTED TO MAINTAIN THE TOP SURFACE OF SAID TABLE IN ANY ONE OF A NUMBER OF POSITIONS INCLUDING A POSITION COINCIDENT WITH SAID HORIZONTAL SURFACE OF SAID LEDGE AND IN POSITIONS GENERALLY IN A PLANE PARALLEL TO AND BELOW SAID HORIZONTAL SURFACE, MEANS TO MOVE THE WORKPIECE ACROSS THE TABLE TOWARDS THE WORK STOP AND TO HOLD THE WORKPIECE DURING MACHINING AGAINST SAID OF SAID STOP AND ALTERNATIVELY AGAINST THE VERTICAL SURFACE OF SAID LEDGE WHEN THE TABLE IS BELOW SAID HORIZONTAL SURFACE, MEANS FOR INTIATING AN INDEXING MOVEMENT OF A WORKPIECE SITUATED ON THE TABLE WHEN THE TABLE IS BELOW SAID HORIZONTAL SURFACE AND FOR EJECTING SAID WORKPIECE FROM SAID TABLE AFTER FINAL MACHINING OPERATION. 